Working with specialized equipment inside Orbiter Processing Facility-3 at NASA’s Kennedy Space Center in Florida, technicians installed the first of three main engines on space shuttle Discovery Monday in preparation for the STS-133 launch targeted for September. The remaining two engines will be installed today as the spacecraft continues its regular preparations for spaceflight. The crew of STS-133 continue to train at NASA’s Johnson Space Center in Houston. Today, the astronauts, led by veteran shuttle commander Steve Lindsey, are involved in a variety of systems training classes.